Australian IVF clinics are offering a test that enables parents to discard embryos that will develop into women at risk of breast cancer.

The tests pick up mutations in the BRCA1 and BRCA2 genes, Dr Leeanda Wilton, head of the Genetic and Molecular Research Lab at Melbourne IVF, told a recent international conference in Brisbane.

But the tests have sparked ethical concerns about whether an embryo should be destroyed on the basis of a risk factor.

Most current tests on embryos are based on detecting those that carry a known genetic disease.

PGD, or preimplantation genetic diagnosis, enables genetic abnormalities to be diagnosed in a very early IVF embryo before it is implanted into the mother.

Originally tests used fluorescent in situ hybridisation (FISH) to determine an embryo's gender and detect whole chromosome disorders that may have made an IVF embryo unlikely to 'take' once implanted.

But newer polymerase chain reaction (PCR) techniques have made it possible to test for a range of single-gene disorders, such as cystic fibrosis, haemophilia and muscular dystrophy.

This technique can also detect mutations in the BRCA genes, which confer an estimated 65-85% risk of the carrier developing breast cancer by the age of 70.

How is PGD done?

A woman with a family history of breast cancer, or who carries the BRCA mutation, can ensure her baby doesn't inherit it by undergoing IVF to create an embryo and testing that embryo before implantation.

To do this, scientists make a tiny hole into the shell around the embryo, gently remove one cell and test it.

If a mutation is found the embryo is discarded. If no mutations are picked up it is implanted in the woman to establish a pregnancy.

While at least three Australian clinics offer the breast cancer tests, demand doesn't yet seem to be high, although experts expect this to change.

Dr Wilton says Melbourne IVF has the technology to test for the breast cancer mutation but hasn't yet done such tests.

"That's predominantly because we haven't been asked to do it," she says.

Dr David Cram, director of molecular genetic services at another large Victorian clinic, Monash IVF, says two patients have requested BRCA screening in the two or three years it's been available.

He expects demand to grow as more young women of child-bearing age find they carry the gene.

"Once systems are in place to identify these mutations more readily, women of a younger age will consider this option when they want to have children," he says.

"I think we'll see some patients take up the technology in the future."

James Marshall, PGD laboratory manager at Sydney IVF, says about three patients have asked for testing and a number clinical geneticists have inquired about it.

"The first patient requests have only been in the last nine months," he says.

Queensland Fertility Group hopes to be able to test for a range of single-gene conditions, probably including breast cancer, by the end of the year, says scientific director Keith Harrison.

"Once you've got a monogenic PGD program then we'd do [all the tests] as long as the gene defect is characterised," he says.

"But it would be an interesting one to run past the ethics committee, because when you're testing for say cystic fibrosis or Huntington's, you're discarding or destroying embryos because they actually carry a moderately lethal defect.

"But the BRCA gene ... isn't a total guarantee you're going to get the disease."

Ethical concerns

Dr Wilton acknowledges there are ethical issues in testing an embryo for breast cancer risk but defends a woman's right to have the test.

"It's not straight forward ethically, that's for sure. But I think what we see is that the patients who come for PGD certainly don't do it on a whim," she says.

"Usually the ones who end up in PGD have usually had a very tragic history of breast cancer.

"If there is a way that her daughters can avoid that it's very easy to understand why patients would want to take that path."

Dr Domenico Coviello is an Italian medical geneticist and head of the Laboratory of Medical Genetics, in Milan.

"Medical geneticists and doctors in general have the aim to help people and cure people ... but I am a little concerned about taking tests, especially on predisposition, and BRCA is only a risk," he says.